Resource exhaustion in Symfony Ux
CVE-2026-49209
Symfony UX is a JavaScript ecosystem for Symfony. From 2.5.0 until 2.36.0 and 3.1.0, Symfony\UX\LiveComponent\Controller\BatchActionController::__invoke() iterates over the client-supplied actions array and issues a full HttpKernel sub-request for each entry; because the array size is never bounded, an authenticated client can submit a single _batch request containing thousands of actions and exhaust CPU, memory, and database connections on the application server. This issue is fixed in versions 2.36.0 and 3.1.0.
EPSS: 0.006 (44.4th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.
Affected products
- Symfony Ux — versions >= 3.0.0, < 3.1.0, >= 2.5.0, < 2.36.0, 3.0.0
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM, Vendor Advisory)
- security-advisories@github.com (Patch, x_refsource_MISC)
- security-advisories@github.com (x_refsource_MISC, Release Notes)
- security-advisories@github.com (x_refsource_MISC, Release Notes)
Frequently asked questions
- What is CVE-2026-49209?
- CVE-2026-49209 is a medium-severity vulnerability in Symfony Ux, classified under Allocation of Resources Without Limits or Throttling. CVSS score: 6.5/10. Published 2026-07-17.
- How severe is CVE-2026-49209?
- Medium severity. CVSS v3 base score is 6.5 out of 10.